Individuals infected with the Human Immunodeficiency Virus (HIV) are now living longer lives as a result of treatment with antiretroviral therapies. Unfortunately, many individuals have difficulty maintaining adequate compliance with their HIV treatment regimens. As life stress has toxic effects on health, well-being, and self- care behaviors, it is hypothesized that life stress also contributes to problematic adherence. This 3-month prospective investigation seeks to examine the impact of life stress on adherence to HIV treatment regimens. Past theory and research suggests that coping plays a key role in how individuals respond to life stressors, and therefore, it is expected that the impact of life stress on treatment adherence will depend on coping style. Further, elevated depressive symptoms are associated with dysfunctional coping, and therefore, it is expected that depression will amplify the effects of stress on adherence. In summary, I will test a model positing that maladaptive coping style (including substance use and social withdrawal) mediates the association between life stress and adherence, particularly among more severely depressed individuals. Results will aid treatment providers in constructing interventions to increase treatment adherence. [unreadable] [unreadable]